Cairo -LRB- CNN -RRB- -- Military police poured into Cairo 's Tahrir Square on Wednesday in hopes of stopping clashes between protesters and police , as the Egyptian government said a truce had been declared through a group of clerics .

The truce lasted about three hours .

CNN saw military police lined up , separating protesters from the police .

But after a period of calm , some protesters began throwing rocks at soldiers . Riot police responded with tear gas ; the unrest continued late Wednesday .

Some army soldiers tried to stop security forces from shooting tear gas , but they were outnumbered .

On state-run TV , the government said religious scholars were on their way `` to form a human shield between the protesters and the security forces . ''

CNN saw no sign of a human shield of clerics . But along the barricades separating protesters from security forces , some clerics were talking to protesters , trying to negotiate .

Egypt 's grand mufti , the country 's highest religious official , called on police to put down their weapons and `` never aim '' firearms at the Egyptian people . In an audio message aired by Egyptian state TV , he called for a `` peaceful protest for Egypt 's sake . ''

Protesters reached Fahmi Street , which leads to the Interior Ministry , and were trying to surround the ministry , state-run Al-Masriya TV said .

Earlier , police pulled back from Mohamed Mahmoud Street , the site of clashes throughout the five days of the latest uprising .

Adel Saeed , spokesman for the Egyptian general prosecutor 's office , said `` a truce has been reached between the protesters and the security forces at the Ministry of Interior through several leading religious scholars . ''

It was not immediately clear who may have been represented in the discussions to which Saeed referred .

Mohamed Mahmoud Street leads from Tahrir Square -- the center of the protests that toppled Hosni Mubarak as president in February and of the most recent demonstrations -- toward the Interior Ministry .

During a lull in the street battles earlier Wednesday , CNN saw riot police embracing and kissing some young people who were taking part in the demonstrations . Minutes later , rocks and tear gas were in the air again .

Protesters erected barriers using debris from burned-out cars and large trash bins in case the battles resumed .

Crowds have packed Tahrir Square since Saturday , calling for the nation 's military rulers to step down immediately . The demonstrations Wednesday were a vociferous rejection of Mohamed Hussein Tantawi , field marshal of the Supreme Council of the Armed Forces , who delivered an address Tuesday aimed at calming the protests .

`` The people demand the downfall of the council of shame , '' some demonstrators chanted Wednesday .

Through the state-run news agency MENA , the government said that the army was `` exerting all efforts to stop bloodshed of Egyptians '' and that the military had deployed three armored vehicles to Mohamed Mahmoud Street .

The death toll in the latest clashes has risen to 35 , including 31 people in Cairo and four in other cities , state-run television said Wednesday .

The number of wounded is up to 3,250 , according to Hisham Sheeha , spokesman for Egypt 's Health Ministry .

Saeed , of the Egyptian general prosecutor 's office , said 312 people had been arrested since Saturday .

Security forces could be seen making arrests Wednesday . Egyptian-American filmmaker Jehane Noujaim was among those arrested , according to Karim Amer , a film producer who said he was with her when she was filming events close to the Interior Ministry .

`` The military started firing tear gas so we all ran in different directions and I lost her , '' Amer said . `` She called me and said she was arrested by military . '' A CNN e-mail to noujaimfilms.com , which lists Noujaim as director , was not immediately returned .

Meanwhile , the mother of one of the three American students detained in Egypt said Wednesday that she was able to speak to him briefly in a telephone call arranged by U.S. diplomats .

`` He sounded scared , but he said he was OK , '' Joy Sweeney said of her son , Derrik Sweeney , one of three American college students being held for questioning in an Egyptian courthouse , accused by authorities of throwing Molotov cocktails in Tahrir Square .

The students will be detained another four days as an investigation continues , said a spokesman for the office of Egypt 's general prosecutor .

An official from the U.S. consular office visited the students , said U.S. Embassy spokeswoman Katharina Gollner-Sweet .

The chaos and fighting have raised new questions about Egypt 's future less than a week before parliamentary elections are set to begin .

U.N. High Commissioner for Human Rights Navi Pillay called on Egypt `` to end the clearly excessive use of force . ''

`` Some of the images coming out of Tahrir , including the brutal beating of already subdued protesters , are deeply shocking , as are the reports of unarmed protesters being shot in the head , '' Pillay said in a statement . `` There should be a prompt , impartial and independent investigation , and accountability for those found responsible for the abuses that have taken place should be ensured . ''

After Mubarak 's ouster , military leaders took control with the promise that eventually a civilian government would be elected and take over .

Demonstrators say they are concerned the military , which would continue to be Egypt 's top authority until a president is in place , wants to keep a grip on the country .

Many also have voiced anger about a proposed constitutional change that would shield the military 's budget from scrutiny by civilian powers . They say they worry the military would become a state within a state .

Members of the nation 's Cabinet offered to resign Monday , with one minister citing concern over the violence in Tahrir Square .

Tantawi of the Supreme Council of the Armed Forces said the resignations were accepted , but the current government will remain as a caretaker until a prime minister is named to form a new government .

Speaking Tuesday on Egyptian TV , Tantawi said the armed forces were `` only concerned about the security of the country and the interests of the country , '' and want to `` establish democracy for the people of Egypt . ''

CNN 's Saad Abedine , Mohamed Fadel Fahmy and Josh Levs and journalists Ian Lee and Mohamed Fadel Fahmy contributed to this report .

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Egypt 's grand mufti calls on police to put down their weapons

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The death toll in five days of violence has risen to 35 , officials say

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The number of injured stands at 3,250 , Egyptian Health Ministry says

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U.N. human rights chief calls on Egypt to stop `` the clearly excessive use of force ''